The development of novel and efficient cyclization methods for the synthesis of biologically significant heterocyclic compounds is planned. The proposed project consists of two major sections. The first section is concerned with the development of new methodologies for the construction of important heterocyclic ring systems. Throughout the first section, we discuss further developments of a recently discovered, novel copper-assisted cycloisomerization reaction of alkynyl imines into pyrroles. Significant attention will be paid to the development of cascade- and sequential protocols, providing rapid and convenient access to condensed pyrrole-containing heterocycles and quinolines. The second section of the project is directed toward development of new synthetic approaches for the expeditious construction of biologically important heterocyclic molecules. To carry out these syntheses, we will rely on using the above-mentioned cyclization protocols. Initially we will examine diastereoselective approaches toward various types of indolizidine alkaloids. We will then explore the feasibility of enantioselectively constructing indolizidine and pyrrolizidine ring systems using these methods. In developing new synthetic methods, an emphasis will be placed on discovering and employing factors necessary for controlling both the selectivity and efficiency of cyclization steps. After completing model studies, the synthesis of biologically important targets will be carried out.The development of highly efficient new heterocyclization methodologies will expand our knowledge of heterocyclic chemistry and provide us with powerful approaches for assembling heterocyclic targets of interest in the health-related sciences.